1. Field of the Invention
The present invention relates to a speaker provided in a communication terminal such as a portable phone, a beeper or the like, and more particularly, the present invention relates to a speaker which has a single device capable of generating incoming call notifying sound and vibration and uses a magnetic field leaking from an outer part of a magnetic circuit section, in a manner such that sufficiently powerful sound and vibration are obtained.
2. Description of the Related Art
Generally, in a portable communication terminal such as a portable phone, a beeper or the like, if an incoming call from an outer source such as a base station is received therein, notification of reception of the incoming call is performed through sound or vibration. To this end, a conventional portable phone or beeper has a sound generating device and a vibration generating device which are separately provided to constitute means for notifying the reception of an incoming call. In this regard, in order to implement a sounding function, a micro speaker, a buzzer, and the like have been used, and, in order to implement a vibrating function, a vibrating motor having a rotation shaft to which an eccentric weight is attached, and the like have been used.
However, the conventional portable phone or beeper including the sound generating device and the vibration generating device which are separately provided, has a problem in that a number of parts is increased and thereby a volume of the portable phone or beeper is also increased, which run counter to miniaturization and lightweightness of the portable phone or beeper.
To cope with this problem, a portable phone or beeper having a speaker which employs a single device so as to generate both of sound and vibration, has been disclosed in the art. Referring to FIG. 1, there is shown an exploded perspective view illustrating a speaker having a single device capable of generating sound and vibration.
As can be readily seen from FIG. 1, a conventional speaker having a single device capable of generating sound and vibration, includes a sound generating section 20 and a magnetic circuit section 40 which is arranged below the sound generating section 20. The sound generating section 20 has a voice coil 24 and a vibrating plate 22 which is assembled to the voice coil 24 to be integrally vibrated therewith. An upper cover 10 covers an upper surface of the vibrating plate 22 to protect the vibrating plate 22. The voice coil 24 is secured to a lower end of the vibrating plate 22. Further, an upper leaf spring 30 is positioned below the vibrating plate 22 in such a way as to vibrate a frame 50. A terminal block 52 is attached to a portion of the frame 50 in a manner such that the terminal block 52 can connect the frame 50 and an external power supply with each other. The magnetic circuit section 40 which is disposed below the upper leaf spring 30, is composed of a plate 42, a magnet 44 and a yoke 46. The terminal block 52 which is attached to the portion of the frame 50, functions to support the magnetic circuit section 40 and transmit vibrating force generated in the magnetic circuit section 40 to the frame 50. Below the frame 50, there are sequentially disposed a lower leaf spring 30 which vibrates the frame 50 and a lower cover 60 which protects the inside of the speaker.
Hereinafter, operations of the conventional speaker constructed as mentioned above will be described. The conventional speaker largely performs a sound generating function and a vibration generating function. First, the sound generating function is performed in a manner described below. That is to say, due to electromagnetic force which is produced by interaction between a magnetic field developed in the magnetic circuit section 40 and an electric field developed in the voice coil 24, driving force is created in the voice coil 24. By the driving force, the voice coil 24 and the vibrating plate 22 which is integrally coupled to the voice coil 24, are driven upward and downward in unison. Therefore, through vibration of the vibrating plate 22, incoming call notifying sound is generated. At this time, a reproduction frequency band for the incoming call notifying sound is selected to be a radio frequency band which serves as an audible frequency band.
On the other hand, the vibration generating function is performed in a low frequency band. By electromagnetic force which is produced in the magnetic circuit section 40 and the voice coil 24, the magnetic circuit section 40 is vibrated upward and downward. This vibrating force is transmitted through the upper and lower leaf springs 30 which are brought into contact with the magnetic circuit section 40, to the frame 50.
However, the conventional speaker having the above-described construction, still suffers from defects in that, since the electromagnetic force which is produced by the interaction between the magnetic field developed in the magnetic circuit section 40 and the electric field developed in the voice coil 24, serves as driving force upon generating sound and upon generating vibration, the driving force is not so powerful that a desired level of driving force cannot be accomplished. In other words, a magnitude of the electric field which is developed only by the voice coil 24, cannot but be limited to a certain value. Also, due to the fact that magnetic flux leakage is induced in an outer part of the magnetic circuit section 40, it is difficult to procure powerful driving force in conformity with a desire of a user.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a speaker which has a single device capable of generating sound and vibration when a radio incoming call is received in a communication terminal such as a portable phone, a beeper or the like, and uses a magnetic field leaking from an outer part of a magnetic circuit section, in a manner such that sufficiently powerful sound and vibration are obtained.
In order to achieve the above object, according to one aspect of the present invention, there is provided a speaker capable of generating sound and vibration for notifying reception of an incoming call when a radio incoming signal is received, the speaker comprising: a cylindrical frame; magnetic field forming means disposed in the cylindrical frame for forming first and second magnetic flux; a sound generating section for producing electromagnetic force by interaction with the first magnetic flux and thereby generating sound, when a signal having a frequency which is no less than a predetermined frequency, is applied thereto; and vibration generating means for producing electromagnetic force by interaction with the second magnetic flux and thereby generating vibration, when a signal having a frequency which is less than the predetermined frequency, is applied thereto.
Preferably, the magnetic field forming means includes an annular plate, an annular magnet and a yoke; the yoke has an annular flange portion, a cylindrical side wall portion which extends upward from a circumferential inner surface of the annular flange portion, and a top disc portion which closes an upper end of the cylindrical side wall portion; the annular magnet and the annular plate are sequentially stacked on the annular flange portion of the yoke in a manner such that the cylindrical side wall portion and the top disc portion of the yoke are inserted into openings which are defined at center portions of the annular magnet and plate and a gap is defined between circumferential inner surfaces of the annular magnet and plate and a circumferential outer surface of the cylindrical side wall portion of the yoke; and the first magnetic flux is formed in the gap and the second magnetic flux is formed outside the annular magnet and plate.
More preferably, the sound generating section includes a vibrating plate and a voice coil; the voice coil is integrally coupled to a lower end of the vibrating plate and is located in the gap; and, when the signal having the frequency which is no less than the predetermined frequency, is applied to the voice coil, the voice coil interacts with the first magnetic flux, and thereby vibrates the vibrating plate and generates sound.
The vibration generating means includes a vibrating coil which is located between a circumferential inner surface of the cylindrical frame and the annular magnet, and a leaf spring which is coupled at one end thereof to a lower surface of the annular flange portion of the yoke to elastically support the yoke and is secured at the other end thereof to the cylindrical frame; the vibrating coil is fixedly supported by the cylindrical frame; and, when the signal having the frequency which is less than the predetermined frequency, is applied to the vibrating coil, the vibrating coil interacts with the second magnetic flux and thereby vibrates the magnetic field forming means. At this time, the vibrating coil can be connected in parallel with the voice coil. Also, the vibrating coil can be connected in series with the voice coil.